Expanding bit screw driver



y 1951 G. AITTO 2,560,912

EXPANDING BIT SCREW DRIVER Filed June 28, 1947 INVENTOR. George AiztoATTORNEY l atented July 17, 1951 UNITED- STATES PATENT OFFICE I I I I2,560,912

EXPANDING BITSCREW DRIVER George Aitto, New York, N. Y.

Application June 28, 1947, Serial No. 757,882

ing the setting of the screw into the hole into which it is to bedriven.

Another object of the invention is the provision of a screw driverhaving the shank thereof formed of two separate sections possessing adegree of resiliency, with the tips thereof complementarily triangularin cross-section and adapted to be moved longitudinally over each otherto fit the width of the slot in the screw head, together with means forso moving the shank sections in either direction.

The above as well as additional objects will become apparent in thefollowing description, wherein characters of reference refer tolikenumbered parts in the accompanying drawing. It is to be noted thatthe drawing is intended for the purpose of illustration only, and thatit is neither desired nor intended to limit the invention necessarily toany or all of the specific details of construction shown exceptinginsofar as they may be deemed essential to the invention.

Referring briefly to the drawing, Fig. l is a front elevational view ofthe screw driver illustrating the invention.

Fig. 2 is a top plan view of the same.

Fig. 3 is a side elevational view of the same.

Fig. 4 is a sectional View taken on the line 4-4 of Fig. 3.

Fig. 5 is a sectional view taken on the line 5-5 of Fig. 4.

Fig. 6 is a front elevational view of the screw driver shank per se.

Fig. '7 is a sectional view taken on the line 1-1 of Fig. 4.

Fig. 8 is a fragmentary perspective view of the tip of the shank.

Fig. 9 is a perspective view showing, fragmentarily the tip of the shankapplied to the head of a screw, the latter having parts broken away andbeing shown partly in section.

Referring in detail to the drawings, the numeral I indicates thebarrel-shaped hollow handle of the screw driver, having the cap Hrotatably mounted on one end thereof and provided with an internalthreaded axial bore l2. The cap ll may be rotatably mounted as stated byany suitable means, such as, for example, by providing pins 13 in thehandle projecting into a circumferential groove [4 in the cap.

The screw driver shank I is split by a slot 16 into two end members orsections I! which are 1 Claim- (Cl. 145-60) bent outwardly intermediatetheir length at l8, and whose extremities are shaped into twocomplementary triangular or wedge-shaped'tips, l9, and HM, thetriangular or wedge-shaped here referred to relating to thecross-sectional areas of the tips and of course to their areas at theirextremities. The lower extremity 20 of the shank I5 is threaded andregisters in the bore I2.

The barrel in is provided with two diametrically opposed longitudinalgrooves 2|, and the shank members H are provided with diametricallyopposed ears 22 which register slidably in these grooves. The upper endof the bore through the barrel [0, tapers, that is, is conical, as shownat 23, so that when the shank is drawn into the barrel the upper ends ofthe members ll. will be urged toward each other as the angularly bent ordeformed portions I8 of these members ride over the tapering surface'23, and conversely, as

the shank is advanced out of the barrel the members I! are urged toseparate because of their inherent resiliency. As the members I! thuscome together, it is apparent that their tips I9 and l9a will slide overeach other and thus increase the thickness of the resultant combined tipof the shank, and conversely, as the members ll separate the thicknessof the combined shank tip will diminish while the Width of the tip willincrease. Thus, the thickness of the screw driver tip may be varied toaccommodate the thickness of the screw slot to facilitate the driving ofa screw and also to enable the screw to be carried on the screw drivertip to its point of application.

The shank I5 is either advanced from or withdrawn into the barrel byrotation of the cap II in one direction or the other. In using the screwdriver to carry a screw to its point of application, the combined tipl9l9a is inserted into the screw slot and the cap H is rotated until thescrew is firmly held. Then the screw is inserted into its hole and thescrew driver is turned in the normal manner, by means of the handle [0,and any further rotation of the cap II will have no elfect other than todrive the screw home.

Obviously, modifications in form and structure will or may be madewithin the spirit or scope of the invention.

I claim:

A screw driver comprising a hollow barrelshaped handle, one end ofsaidhandle having an annular recess therein coaxial with axis of thehandle, a cap having a boss registering rotatably in said recess, saidboss having a cir-.

cumferential groove therein, said handle having of said recess andregistering in said groove, the other end of said handle being open,said open end having a mouth, a shank of greater length than the handlemounted in said handle, said cap having a threaded axial bore, saidshank having one extremity threaded and registering in said cap bore,said shank having a split therethrough extending from the otherextremity thereof to a point intermediate the length of the shankthereby dividing the shank into two sections, said shank being made of aresilient material and having said sections normally positioned inseparated condition, said sections being deformed angularly anddivergently at the neighborhood of said mouth whereby the deformedportions thereof are urged by said resiliency against said mouth, saidsections having extensions thereon of equal length extendingconvergently toward each other at acute angles to said sections, theextremities of said extensions comprising mutually complementarywedge-shaped tips adapted to slide together and to be brought togetherto form a unitary substantially rectangular tip for the screw driver,said handle having diametrically opposed longitudinal internal grooves,said shank sections having ears registering in said grooves, rotation ofsaid cap with respect to said handle in one direction causing said shankto be drawn into the barrel and thereby causing said shank sections andsaid extension tips to be brought together, rotation of said cap in theopposite direction permitting said resiliency to urge said shanksections and said extension tips to separate.

GEORGE AITTO.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

